Firing mechanism



w. SUMMERBELL 2,366,758

FIRING MECHANISM Filed July 16, 1942 2 Sheets-Sheet 1 Fig.1

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Jan 9, 1945. w, SUMMERBELL 2,366,758

FIRING MECHANISM Filed July 16, 1942 2 Sheets-Sheet 2 mlli am 51.1mm21'']: E11

@XM MW Patented Jan. 9, 1945 were UNITED STATES PATENT OFFICE 2,366,758FIRING MECHANISM William Summerbell, Washington, D. 0. Application July16, i942, Serial No. 451,192

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370O. G. 757) 8 Claims.

This invention relates to a. percussive firing mechanism and moreparticularly to such a mechanism for a breech loading gun of theseparate loading type, wherein a primer cartridge is fired through apassage in the obturator to ignite the main charge.

"It is an object of this invention to provide an improved firingmechanism of the type in which a single continuous pull of the lanyardserves to tension the firing pin spring and to release-the same to drivethe firing pin to firing position.

It is a further object to provide a firing mechanism in which the firingpin spring is rendered inoperative in the later part of the firingstroke to enable the firing pin to move to firing position under its owninertia and to provide for immediate retraction of the firing pinsufficient to clear the primer cartridge.

An additional object is to provide improved means of securing a primercartridge to the firing mechanism and to provide for automatic controlof, the headspacing thereof thus improving the certainty of firing.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown'in the accompanying drawingsin which:

Figure l is a top plan view of the firing mechanism and a portion ofthebreech block.

Figure 2 is a rear end elevational view correspondin to Figure 1.

Figure 3 is a horizontal longitudinal sectional view on the line 3-3 ofFigure 2.

Figure 4 is a front elevational view of a part of the firing mechanism.

Figure 5 is a vertical longitudinal sectional View of the pull rod andtripper mechanism taken on the line 55 of Figure 3.

Figure 6 is a longitudinal sectional view of the firing pin sleeve.

Figure '7 is an end elevational view corresponding to Figure 6.

Figure 8 is a longitudinal sectional view of the spring stop collar.

Figure 9 is a partial horizontal longitudinal sectional view showing thetripper and sear'in a retracted position taken in the same plane asFigure 3.

Figure 10 is a partial longitudinal sectional view in the same plane asFigure 3 showing a modified firing pin retracting means.

Referring to the drawings by characters of reference there is shown aportion I of an obturator breech mechanism of conventional form. Themember 1 comprises a chamber defining member 2 housing a primercartridge 3 and an axial bore l leading to the powder chamber of theweapon. The member I also includes a rearwardly opening bore 5 coaxialwith the member 2' and provided with internal threads 6 for thereception of the firing mechanism.

Broadly the firing mechanism comprises an ex.- ternally threaded block 1adapted to screw into the bore 5 and means to secure thereto the primercartridge 3 in axial alignment with the chamber in the member 2. Afiring mechanism housing 8 is secured to the rear end of the block 7 andhouses the firing pin 9, firing pin sprin H1, tripper ll, pull rod [2and associated parts to be described in more detail later. A retainer I3is provided to secure the firing mechanism within th housing andjournals are provided on the housing to support the trigger arm M whichis provided with means to engage the pull rod for actuation of thefiring mechanism on pulling a lanyard attached to the eye I5. Thehousing is further provided with a radially slidable, spring restrainedlatch l6 adapted to engage in the teeth of a ratchet I! secured to therear face of the member I for releasablyretaining the firing mechanismin the bore.

Referring to the drawings in more detail Figure 4 shows a frontelevational View of the primer holder l8 into which the primer cartridgemay be inserted from the side and secured by engagement of the extractorgroove with the lip is;

From an inspection of Figure 3 it will be seen that the firing pin guide20 has a limited capacity for axial movement in the block I and that thefiring pin spring 10 through the medium of the stop collar 2| normallyurges the guide 28 forwardly into a position in which the primercartridge is firmly gripped "by engagement between the lip l9 of theprimer holder and the front face of the firing pin guide 28. Thisengagement prevents dropping or displacement of the primer cartridgeprior to insertion in the chamber and insures that the headspacing ofthe primer cartridge'will be maintained correct for insuring 'eflicientignition. v

I The firing pin 9 is threadably secured to the firing pin sleeve' 22,shown'in detail in Figures 6 and '7, and the front face of the head 23of the firing pin is engaged by the rear face of the inner flange 24 ofthe retracting collar 25. A stop collar 2i is slidable on the firing pinand has legs 26 projectin 'through the-cut out portions 21 of the sleeve22. The firing pin spring I is engaged between the rear face of thespring stop collar 2! and the front face of the outer flange 28 of theretracting collar 25. A retainer it has a portion 29 of reduced diameterextending forwardly into the housing and is provided on the forward endthereof with a pair of opposed locking ears 30. In assembly the retaineris inserted into the end of the housing, the cars 30 passing through cutaway openings 3|, pressed forwardly againstthe resistance of the firingpin spring, and given a quarter turn to bring the cars 30 into alignmentwith the partially cut out seats 32 in th housing in which it is. heldby the firing pin spring. Disassembly is effected by a reversal of theabove procedure. The'firing pin retracting device functions generally inthe same manner as that shown in my prior Patent No. 2,245,621. Brieflythe sleeve 22 is moved rearwardly by the engagement of a tripper H withthe flange 33 surrounding the rear end of the sleeve. As the sleeve ismoved rearwardly it carries with it the stop collar 2! and tensions thespring l0. Upon release ofthe sleeve from the tripper the firing pin,sleeve, and stop collar are impelled forwardly by the spring until thelegs 26 of the spring stop collar contact the rear face of the firingpin guide 20. The sleeve and firing pin continue due to their owninertia and the firing pin forceably engages the primer. However, as thehead 23 of the firing pin engages the inner flange 24' of the retractingcollar, the collar will be carried forward by the firing pin during itslatter phase of motion and will serve to place tension on the firing pinspring tending to withdraw the pin from the primer and return it to thenormal, retracted position in which it is shown in Figure 3, and inwhich it offers no obstruction to insertion or removal of the primercartridges.

The tripper II, as has been mentioned above, engages the flange 33 intensioning the spring. The tripper is pivotably mounted in thebifurcated end of the pull rod H! which i slidable axially in the bore34 and carries on its exposed end the button 35 engaging the tripper pin36 on the trigger arm [4. A bushing 31 is slidable on the pull rod andis provided on its upper side with a'slot 38 of sufficient width toallow the finger 39 of the tripper H to swing therethrough. A pull rodspring 40 is confined on the pull rod between the bushing 31 and the endof the firing mechanism housing serving to yieldingly maintain the pullrod within the housing and to hold the bushing 31 as far to the right inFigure 3 as it may go. It will be noted that the foot 4| of the tripperII is of greater width than the finger 39, see Figure 5, providingshoulders 42 which engage the front face of the bushing and will retractthe bushing slightly as shown in Figure 9 when the tripperis rocked ineither direction. Thus the action of the spring against the bushingconstantly urges the finger of the tripper into flange engagingposition. The forward end of the bore 34 has a portion 43 of enlargeddiameter and when the pull rod is drawn to the rear by the tripper thefoot 4! of the tripper engages the shoulder 44 at the transition zonebetween the two diameters of boreand forces the finger 39v out ofengagement with the flange 33 on the firing pin sleeve at the time whenthe firing pin spring is fully tensioned.

It will be seen from the foregoing that a Single operation of thetrigger results in carrying the firing pin to the rear and tensioningthe firing pin spring in which position the finger is released by thecamming action of the shoulder upon the tripper foot and the firing pinis driven forwardly to initiate the primer. Upon completion of theforward stroke the firing spring will have been retensioned to an extentsufficient to withdraw the firing pin to a safe retracted position.

Figure 10 shOWS a modified form of the invention in which a separatespring is utilized to effect retraction of the firing pin. In thismodification a firing pin 45 is threadably supported in the firing pinsleeve 22a but does not necessarily extend rearwardly therewithin.Slidable on the firing pin and retained thereon by a nut 46 is a bushing41 which is normally maintained in an extended position by a spring 48engaged between the flange on the bushing and the front face of thesleeve 22a. A rearwardly facing shoulder 49 is provided in coaxialrelation to the passage through the firing pin guide 20a and serves toengage the bushing when the firing pin is driven forward under its ownmomentum in the last phase of its firing stroke after the stop collar26a has contacted the guide 20a. When the momentum has been absorbed byimpact with the primer the compressed retracting spring 48 will extenditself and retract the firing pin. In other respects the modified formfunctions as described above.

As this firing mechanism is intended to be capable of functioning withequal facility for guns, howitzers, or mortars the trigger arm has beendesigned to permit operation either by pulling the lanyard to one sideor in a generally rearward direction. Firing mechanisms which require arearward pull are highly inconvenient at the high angles of elevationemployed with howitzers and mortars. It will be appreciated that thefiring mechanism shown will allow the gun crews to take advantage of anycover which may be available without interfering with efficientoperation of the firing mechanism.

I claim:

1. In a firing mechanism, a pull rod having a bifurcated end, a tripperpivoted in said end, a spring encircling said pull rod and opposingrearward movement thereof, and a bushing surrounding the pull rodengaged by the spring to bias said tripper to a predetermined angularposition with respect to said pull rod.

2. In a firing mechanism, a pull rod, a bifurcated end on said pull rod,a tripper comprising a finger pivoted in the bifurcated end of said pullrod and having a foot of greater width than said finger forming acontinuation thereof beyond the pivotal point of said finger, a bushingslidable on said pull rod and having a slot to allow said finger tooscillate therethrough, means on said bushing engaging the foot on saidtripper, and spring means engaging said bushing tending to move the sametoward said tripper.

3. In a firing mechanism, a pull rod, an enlarged bifurcated endproviding arms on said pull rod, a pivot pin spanning the arms of saidpull rod, a tripper comprising a finger received be tween the arms ofsaid pull rod and oscillatable about said pivot, a bushing slidable onthe said pull rod and continuing over the bifurcated end, and having aslot therein through which said fin- 'ger is oscillatable, a. foot onsaid tripper of greater width than said finger and engageable with theend of said bushing when said tripper is oscillated, and a springencircling said pull rod tend- 4. In a firing mechanism, a breech block,a stationary primer holder in the block and having a side opening forinsertion of a primer cartridge and a lip for engagement with the groovein the primer cartridge, a firing pin guide slidably mounted in saidholder, a firing pin, a firing pin sleeve, a stop collar surrounding thefiring pin within the sleeve and having extensions extending throughsaid sleeve into engagement with the rear face of the firing pin guideto hold said guide in engagement with the primer cartridge, a springsurrounding the firing pin and normally urging said stop collar and pinforwardly, means for moving said firing pin rearward against thepressure of said spring, and means for releasing said pin at anappropriate point in its rearward movement.

5. In a firing mechanism, a breech block, a stationary primer holder insaid block and having a side opening for insertion of a primer cartridgeand a lip for engagement with the groove in the primer cartridge, afiring pin guide slidably mounted in said holder, a firing pin, a firingpin sleeve having a sear-engaging portion on its periphery adjacent itsrear end, a stop collarwithin the sleeve and surrounding the firing inand having forward extensions extending through the firing pin sleeveinto engagement with the face of the firing pin guide to hold said guidein engagement with the primer cartridge, a spring surrounding the firingpin and urging the collar against the guide, a pull rod, and means forurging it-normally forward, a sear pivoted in said pull rod and normallyengaging the sear-engag-' ing portion of said sleeve, and means fordisengaging the sear from said sleeve portion at a predetermined pointin the rearward movement of the pull rod.

6. In a firing mechanism, a pull rod, a tripper pivoted to one end ofsaid rod, a spring encircling said pull rod and opposing rearwardmovement thereof, and a bushing surrounding a portion of said pull rodengaged by the spring to bias said tripper to a predetermined angularposition with respect to said pull rod.

7. In a firing mechanism, a pull rod, a tripper comprising a finger andfoot portions pivoted to one end of said pull rod, a bushing slidable onsaid pull rod and having a slot to allow said finger to oscillatetherethrough, means on said tripper engaging one end ofsaid bushing, andspring means engaging the other end of said bushing tending to move thesame toward said tripper.

8. In a firing mechanism, a pull rod, a tripper comprising a fingerpivoted to one end of said pull rod and having a foot of greater widththan .said finger forming a continuation thereof beyond the pivotalpoint of said finger, a bushing slidable on said pull rod and having aslot to allow said finger to oscillate therethrough, means on saidbushing engaging the foot on said tripper and spring means engaging saidbushing tending to move the'same toward said tripper.

WILLIAM SUMMERBELL.

